poweroff, reboot, halt - Power off, reboot, or halt the machine
poweroff, reboot, and halt may be used to power off, reboot, or halt the machine. All three commands take the same options.
The following options are understood:
On success, 0 is returned, a non-zero failure code otherwise.
These commands are implemented in a way that preserves basic compatibility with the original SysV commands. systemctl(1) verbs poweroff, reboot, halt provide the same functionality with some additional features.
Note that on many SysV systems halt used to be synonymous to poweroff, i.e. both commands would equally result in powering the machine off. systemd is more accurate here, and halt results in halting the machine only (leaving power on), and poweroff is required to actually power it off.